Paste supply apparatus, screen printing machine, paste supply method and screen printing method

ABSTRACT

A paste supply apparatus includes a plurality of paste pots each including a tubular container which stores paste and which includes a bottom portion provided with a through hole and a movable inner lid provided in the tubular container, and a pot holder which holds the paste pots so as to be horizontally arranged along an arrangement direction such that the through hole of each of the paste pots is directed downward and downward movement of the tubular container thereof is regulated. The paste supply apparatus further includes a pot holder moving device which moves the pot holder along the arrangement direction and selectively positions one of the plurality of paste pots at an ejection position, and a paste ejecting device which presses the inner lid of the paste pot positioned at the ejection position and which ejects the paste in the tubular container from the through hole.

BACKGROUND

1. Technical Field

An aspect of the present invention relates to a paste supply apparatusfor supplying paste to a mask positioned to contact a substrate in ascreen printing machine, the screen printing machine, a paste supplymethod and a screen printing method.

2. Background Art

As a paste supply apparatus for supplying paste to a mask positioned tocontact a substrate in a screen printing machine, JP-A-2011-140176describes an apparatus for ejecting and supplying paste to a mask from asyringe in which the paste is stored. The paste stored in the syringe isprovided from a hermetically closed container called a paste pot filledwith paste. The paste pot includes a tubular container and an inner lidinserted into the tubular container. JP-A-2010-172928 describes a pastesupply apparatus which uses the paste pot itself as a syringe ratherthan refilling the syringe with paste from the paste pot.

SUMMARY

However, in the case of using the paste pot itself as the syringe asdescribed above, paste supply cannot be continued unless the paste potis replaced with a new paste pot when ejection of the paste in the pastepot is completed. Consequently, work efficiency decreases sinceoperation of whole functions of the screen printing machine must bestopped in order to replace the paste pot.

An object of an aspect of the invention is to provide a paste supplyapparatus, a screen printing machine, a paste supply method and a screenprinting method, which can replace a paste pot without stoppingoperation of whole functions of the screen printing machine.

In a first aspect, a paste supply apparatus includes: a plurality ofpaste pots, each of which includes a tubular container which storespaste and which includes a bottom portion provided with a through holeand a movable inner lid provided in the tubular container; a pot holderwhich holds the plurality of paste pots so as to be horizontallyarranged along an arrangement direction such that the through hole ofeach of the plurality of paste pots is directed downward and downwardmovement of the tubular container thereof is regulated; a pot holdermoving device which moves the pot holder along the arrangement directionand which selectively positions one of the plurality of paste pots at anejection position; and a paste ejecting device which presses the innerlid of the paste pot positioned at the ejection position by the potholder moving device with respect to the tubular container and whichejects the paste stored in the tubular container from the through hole.

In a second aspect, a screen printing machine includes: a mask which ispositioned to contact a substrate; a paste supply apparatus according tothe first aspect, which ejects and supplies the paste to the maskcontacting the substrate; and a squeegee slid on the mask to which thepaste is supplied by the paste supply apparatus.

In a third aspect, a paste supply method includes: holding a pluralityof paste pots, each of which includes a tubular container which storespaste and which includes a bottom portion provided with a through holeand a movable inner lid provided in the tubular container, so as to behorizontally arranged along an arrangement direction in a pot holdersuch that the through hole of each of the plurality of paste pots isdirected downward and downward movement of the tubular container thereofis regulated; moving the pot holder in the arrangement direction andselectively positioning one of the plurality of paste pots at anejection position; and pressing the inner lid of the paste potpositioned at the ejection position with respect to the tubularcontainer and ejecting the paste stored in the tubular container fromthe through hole.

In a fourth aspect, a screen printing method includes: positioning amask to contact a substrate; ejecting and supplying the paste from thepaste supply apparatus according to the first aspect to the maskcontacting the substrate; and sliding a squeegee on the mask to whichthe paste is supplied.

According to an aspect of the invention, after ejection of paste in onepaste pot (first paste pot) is completed, another paste pot (secondpaste pot) is positioned at the ejection position and also the empty(first) paste pot is positioned at a position deviating from theejection position. Consequently, the paste can subsequently be ejectedfrom the second paste pot. Further, during that period, the empty(first) paste pot can be replaced with a new paste pot, whereby thepaste pot can be replaced without stopping operation of whole functionsof the apparatus (for example, the screen printing machine) whichreceives supply of the paste. Therefore, work efficiency can beimproved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a screen printing machine in one embodiment ofthe invention;

FIG. 2 is a plan view of the screen printing machine in one embodimentof the invention;

FIG. 3 is a perspective view of a squeegee unit and a paste supplyapparatus provided in the screen printing machine in one embodiment ofthe invention;

FIG. 4A is a perspective view of the paste supply apparatus in oneembodiment of the invention, and FIG. 4B is a partially sectional frontview of the paste supply apparatus;

FIGS. 5A to 5C are perspective views of a paste pot used in the pastesupply apparatus in one embodiment of the invention;

FIG. 6 is a block diagram showing a control system of the screenprinting machine in one embodiment of the invention;

FIGS. 7A to 7C are operation explanatory diagrams of the paste supplyapparatus in one embodiment of the invention;

FIGS. 8A to 8C are operation explanatory diagrams of the paste supplyapparatus in one embodiment of the invention;

FIGS. 9A to 9C are operation explanatory diagrams of the paste supplyapparatus in one embodiment of the invention;

FIGS. 10A to 10C are operation explanatory diagrams of the paste supplyapparatus in one embodiment of the invention;

FIG. 11 is a side view of the screen printing machine in one embodimentof the invention; and

FIG. 12A is a partially sectional front view of a paste supply apparatusin a modification of one embodiment of the invention, and FIGS. 12B and12C are side views of the paste supply apparatus.

DETAILED DESCRIPTION

An embodiment of the invention will hereinafter be described withreference to the drawings. A screen printing machine 1 shown in FIGS. 1and 2 is a machine for repeatedly performing screen printing of pastePst such as solder paste on a substrate 2. The screen printing machine 1includes: a substrate holding/moving unit 4 which is provided on a base3 and which holds and moves the substrate 2; a mask 5 horizontallydisposed above the substrate holding/moving unit 4; a squeegee unit 6provided above the mask 5; a camera unit 7 provided under the mask 5;and a paste supply apparatus 8 provided integrally with the squeegeeunit 6 above the mask 5.

As shown in FIG. 1, the substrate holding/moving unit 4 includes: an XYθmovement mechanism 11 provided on the base 3; a base table 12 which ismovable on a horizontal plane and rotatable around a vertical axis bythe XYθ movement mechanism 11. The substrate holding/moving unit 4further includes a first lifting table 13 and a second lifting table 14,which are provided on the base table 12 in this order from the downwardside.

The XYθ movement mechanism 11 includes a stack of a Y-axis table 11 a,an X-axis table 11 b and a θ table 11 c. The Y-axis table 11 a extendsin a Y-axis direction (a front-back direction viewed from an operator OPshown in FIG. 2, and the left-right direction in FIG. 1) on the base 3.The X-axis table 11 b extends along an X-axis direction (the left-rightdirection viewed from the operator OP, and the direction orthogonal tothe sheet of FIG. 1) on the Y-axis table 11 a. The θ table 11 c isprovided on the X-axis table 11 b. The X-axis table 11 b is moved on theY-axis table 11 a along the Y-axis direction by driving of the Y-axistable 11 a, and the θ table 11 c is moved on the X-axis table 11 b alongthe X-axis direction by driving of the X-axis table 11 b, and the basetable 12 is rotated around vertical axis (Z axis) in FIG. 1 by drivingof the θ table 11 c. That is, the base table 12 is moved in thehorizontal plane by an XYθ movement mechanism 11. The first liftingtable 13 is moved upward and downward with respect to the base table 12by driving of a first lifting table moving motor 13 m, and the secondlifting table 14 is moved upward and downward with respect to the firstlifting table 13 by driving of a second lifting table moving motor 14 m.

A pair of conveyor support members 15 is provided to extend upward fromthe first lifting table 13 and penetrate the second lifting table 14.The pair of conveyor support members 15 supports a pair of conveyors 16extending in the X-axis direction. The conveyors 16 oppose each other inthe Y-axis direction. The pair of conveyors 16 supports both ends of thesubstrate 2 from the downward side and conveys the substrate 2 in theX-axis direction. On an upper surface of the second lifting table 14, areceiving member 17 is provided.

A pair of clamp members (clampers 18) extending along the Y-axisdirection and opposing each other in the X-axis direction is provided onan upper side of the pair of conveyors 16. The pair of clampers 18 isopened and closed in the Y-axis direction by actuation of a damperopen/close cylinder 18 s, and grasps and holds (clamps) both ends of thesubstrate 2 on the conveyors 16.

As shown in FIG. 2, the mask 5 includes: a plate portion 5 a with a flatplate shape extending in an XY plane; and a frame-shaped portion 5 b forholding the outer periphery of the plate portion 5 a. An inside of arectangular region of the plate portion 5 a surrounded by theframe-shaped portion 5 b is provided with pattern holes 5 h so as tocorrespond to electrodes 2 a formed on the substrate 2.

In FIG. 2, the substrate 2 includes a set of two substrate side marks 2m at diagonal positions thereof, and the plate portion 5 a of the mask 5includes a set of two mask side marks 5 m arranged to correspond to thesubstrate side marks 2 m. When the substrate 2 is positioned to contactthe mask 5 in a state in which the substrate side marks 2 m overlap withthe mask side marks 5 m in plan view, the electrodes 2 a of thesubstrate 2 become matching with the pattern holes 5 h of the mask 5.

In FIGS. 1 to 3, the squeegee unit 6 includes: a squeegee base 21extending in the X-axis direction; two squeegees 22 which are providedbelow the squeegee base 21 and arranged to oppose each other in theY-axis direction; and a squeegee unit moving mechanism 23 which movesthe squeegee base 21 in the Y-axis direction. The squeegee unit movingmechanism 23 includes: a pair of squeegee unit moving ball screws 23 awhich are arranged to oppose each other in the X-axis direction andextend in the Y-axis direction above the mask 5; and two squeegee unitmoving motors 23 b which rotate and drive the respective squeegee unitmoving ball screws 23 a. The squeegee unit moving ball screws 23 a arerespectively screwed through the left and right ends of the squeegeebase 21. As a result, when the squeegee unit moving ball screws 23 a arerotated forward or backward in synchronization by the two squeegee unitmoving motors 23 b, the squeegee base 21 is moved along the Y-axisdirection according to this rotation. The two squeegees 22 areindividually moved upward and downward with respect to the squeegee base21 by a squeegee moving cylinder 24 formed on the squeegee base 21.

In FIGS. 1 and 2, the camera unit 7 includes: an upward imaging camera31 with an imaging visual field oriented upward; and a downward imagingcamera 32 with an imaging visual field oriented downward. The cameraunit 7 is moved in a horizontal plane by a camera unit moving mechanism33.

In FIGS. 1 and 2, the paste supply apparatus 8 ejects and supplies thepaste Pst to the mask 5 positioned to contact the substrate 2, and isprovided on the front side of the squeegee base 21. As shown in FIG. 3,a pair of guide members 41 extending in the X-axis direction is arrangedon upper and lower positions in the front of the squeegee base 21, and aball screw 43 extending in the X-axis direction is screwed through ablock member 42 guided to the pair of guide members 41. The ball screw43 is rotatable by a paste supply apparatus moving motor 44 provided onthe end of the squeegee base 21, and the block member 42 is moved in theX-axis direction by forward and backward rotation of the ball screw 43by the paste supply apparatus moving motor 44.

As shown in FIGS. 3, 4A and 4B, the paste supply apparatus 8 includes: abase plate 51 attached to the block member 42 and extending in avertical direction; a moving cylinder 52 made of, for example, arod-less cylinder provided on the front of the base plate 51 so as toextend along the X-axis direction; a pot holder 54 including a baseportion 81 movable along the X-axis direction on a guide 53 extendingalong the X-axis direction by the moving cylinder 52; and a pressingcylinder 55 provided above the pot holder 54. The pot holder 54 holds aplurality of paste pots 61 (two paste pots, in the embodiment) storingthe paste Pst in a state in which the paste pots 61 are arranged alongthe X-axis direction.

The paste pot 61 stores the paste Pst in a tubular container 71 having athrough hole 61S in a bottom portion 71 a. Before use of the paste pot61, a cap CP attached to an open end thereof is detached (from FIG. 5Ato FIG. 5B), and the paste pot 61 is changed in an attitude in which thethrough hole 61S is directed downward (FIG. 5C).

In FIGS. 3, 4A and 4B, the pot holder 54 includes a horizontal flatplate-shaped member, and has two pot insertion holes 54H arranged alongthe X-axis direction. The pot insertion holes 54H receives the pastepots 61 with the caps CP detached from above.

Each of the paste pots 61 is inserted into the corresponding potinsertion hole 54H of the pot holder 54 from above with the attitude inwhich the through hole 61S is directed downward. Then, each of the pastepots 61 is attached to the pot holder 54 by abutting a brim portion 71T(FIGS. 3 and 5A to 5D) formed on a side surface of the tubular container71 on an edge portion of the pot insertion hole 54H from above.Accordingly, the two paste pots 61 are arranged and held in thehorizontal direction (X-axis direction) such that the through hole 61Sis directed downward and downward movement of the tubular container 71is regulated by the pot holder 54 (FIGS. 3, 4A and 4B).

The moving cylinder 52 can move a moving body 52 a from side to side(along the X-axis direction) by supplying and draining air to and fromleft and right ports 52 p, thereby moving the pot holder 54 joined tothe moving body 52 a from side to side. The pot holder 54 is selectivelypositioned at a first position (position shown in FIG. 3) or a secondposition by the moving cylinder 52. At the first position, the paste pot61 inserted into the left pot insertion hole 54H is positioned at anejection position, and the paste pot 61 inserted into the right potinsertion hole 54H is positioned at a standby position deviating fromthe ejection position. At the second position, the paste pot 61 insertedinto the right pot insertion hole 54H is positioned at the ejectionposition, and the paste pot 61 inserted into the left pot insertion hole54H is positioned at the standby position deviating from the ejectionposition. That is, in the embodiment, the moving cylinder 52 serves asan example of a pot holder moving device which moves the pot holder 54along the direction (X-axis direction) in which the plurality of (two,in the embodiment) paste pots 61 are arranged, and which selectivelypositions one of the plurality of paste pots 61 at the ejectionposition. The ejection position is a position at which the paste Pststored in the paste pot 61 is ejected. In the embodiment, the ejectionposition is a position at which the paste Pst can be pressed by thepressing cylinder 55. For example, the ejection position is locatedbelow the pressing cylinder 55, and the drawings of the embodiment showthe ejection position located immediately below or substantiallyimmediately below the pressing cylinder 55. The ejection position is notlimited thereto as long as the paste Pst stored in the paste pot 61 canbe ejected by the screen printing machine 1.

In FIGS. 3 and 4B, the pressing cylinder 55 is attached to an upperregion of the base plate 51 such that a piston rod 55 a is directeddownward, and a pad member 55 b is attached to a lower end of the pistonrod 55 a. When the pressing cylinder 55 moves the piston rod 55 adownward to protrude, the pad member 55 b depresses an inner lid 72 ofthe paste pot 61 (downward movement of the tubular container 71 of thepaste pot 61 is regulated as described above) positioned at the ejectionposition with respect to the tubular container 71, thereby applyingpressure to the paste Pst stored in the tubular container 71 andejecting the paste Pst downward from the through hole 61S.

In the embodiment, the pressing cylinder 55 serves as an example of apaste ejecting device which presses the inner lid 72 of the paste pot 61positioned at the ejection position by the moving cylinder 52 withrespect to the tubular container 71 and which ejects the paste from thethrough hole 61S.

The screen printing machine 1 includes a controller 100. The controller100 controls: conveyance operation of the substrate 2 in the X-axisdirection by the conveyors 16 of the substrate holding/moving unit 4;upward and downward movement operation (support operation of a lowersurface of the substrate 2 described below) of the second lifting table14 by the second lifting table moving motor 14 m; substrate clampoperation of the clampers 18 by the clamper open/close cylinder 18 s;movement operation of the substrate 2 in the horizontal plane by the XYθmovement mechanism 11; and upward and downward movement operation(upward and downward movement operation of the clamped substrate 2described below) of the first lifting table 13 by the first liftingtable moving motor 13 m (FIG. 6). The controller 100 also controls:movement operation of the squeegee unit 6 and the paste supply apparatus8 along the Y-axis direction by the squeegee unit moving motors 23 b;movement operation of the paste supply apparatus 8 along the X-axisdirection by the paste supply apparatus moving motor 44; and upward anddownward movement operation of each of the squeegees 22 by the squeegeemoving cylinder 24 (FIG. 6). The controller 100 also controls: movementoperation of the pot holder 54 along the X-axis direction by the movingcylinder 52; and ejection operation of the paste Pst from the paste pot61 by the pressing cylinder 55 (FIG. 6).

The controller 100 controls movement operation of the camera unit 7 inthe horizontal plane by the camera unit moving mechanism 33; imagingoperation of the upward imaging camera 31 provided in the camera unit 7;and imaging operation of the downward imaging camera 32 provided in thecamera unit 7 (FIG. 6). The image data obtained by the imaging operationof the upward imaging camera 31 and the image data the imaging operationof the downward imaging camera 32 are inputted to the controller 100,and image recognition processing is performed in an image recognitionunit 100 a (FIG. 6).

A supply procedure of the paste Pst (paste supply method) performed bythe paste supply apparatus 8 will be described. At first, the operatorOP inserts the two paste pots 61 into the two pot insertion holes 54H ofthe pot holder 54 from above (FIG. 3), respectively, so as to hold thepaste pots 61 to be horizontally arranged in the pot holding part 54such that the through holes 61S are directed downward and downwardmovement thereof is regulated (a pot holding step). In addition, thepaste pot 61 is inserted into the pot insertion hole 54H in a state inwhich the pot insertion hole 54H is positioned at the standby positiondeviating from the ejection position.

In a state in which the two paste pots 61 are held in the pot holder 54as described above, the controller 100 actuates the moving cylinder 52to move the piston rod 55 a downward to protrude while the pot holder 54is positioned at the first position (that is, the left paste pot 61 ispositioned at the ejection position) (FIG. 7A; arrow A1). Accordingly,the inner lid 72 is depressed with respect to the tubular container 71and the paste Pst is ejected downward from the through hole 61S of theleft paste pot 61. Ejection of the paste Pst from the paste pot 61 iscompleted at the time when the inner lid 72 abuts on the bottom portion71 a of the tubular container 71 (FIG. 7B). The completion of ejectionof the paste Pst in the paste pot 61 positioned at the ejection positionis detected by an ejection completion detector 55 c (FIG. 6) such as astroke sensor which is provided inside the pressing cylinder 55 andwhich detects a stroke of the piston rod 55 a.

After ejection of the paste Pst from the left paste pot 61 is started,if the ejection completion detector 55 c detects completion of ejectionof the paste Pst in the paste pot 61 (FIG. 7B), the controller 100actuates the pressing cylinder 55 to move in a direction (i.e., upwarddirection) opposite to the direction at the time of depressing the innerlid 72 so as to position the pad member 55 b above the left paste pot 61(FIG. 7C; arrow A2). Then, the controller 100 actuates the movingcylinder 52 so as to position the pot holder 54 at the second position,whereby the right paste pot 61 is positioned at the ejection position(FIG. 8A; arrow B1). In other words, the paste pot 61 (empty paste pot61) having existed at the ejection position is positioned at the standbyposition deviating from the ejection position, and the paste pot 61 (newpaste pot 61) having existed at the standby position is positioned atthe ejection position. After the right paste pot 61 is positioned at theejection position, the controller 100 moves the piston rod 55 a downwardto protrude (FIG. 8B; arrow A1). Accordingly, the inner lid 72 isdepressed with respect to the tubular container 71, and the paste Pst isejected downward from the through hole 61S of the right paste pot 61(FIG. 8B).

When or after the pot holder 54 is switched from the first position tothe second position, the controller 100 actuates a notification device101 (FIG. 6) such as a lamp connected to the controller 100 so as toprovide notification that the empty paste pot 61 should be replaced witha new paste pot 61. Based on notification operation by the notificationdevice 101, the operator OP watches for a timing when ejection operationof the paste Pst by the paste supply apparatus 8 is not performed, andat the timing, the operator OP removes the left empty paste pot 61 fromthe left pot insertion hole 54H (FIG. 8C; arrow C1) and then inserts thenew paste pot 61 into the left pot insertion hole 54H so as to hold thenew paste pot 61 in the pot holder 54 (FIG. 9A; arrow C2). Thereplacement work of the paste pot 61 is very easy, thereby being capableof being performed without stopping operation of whole functions of thescreen printing machine 1.

After ejection of the paste Pst from the right paste pot 61 is started,if the ejection completion detector 55 c detects completion of ejectionof the paste Pst in the paste pot 61 (FIG. 9B; arrow A1), the controller100 actuates the pressing cylinder 55 in a direction (i.e., upwarddirection) opposite to the direction at the time of depressing the innerlid 72 so as to position the pad member 55 b above the right paste pot61 (FIG. 9C; arrow A2). Then, the controller 100 actuates the movingcylinder 52 so as to position the left paste pot 61 at the ejectionposition (FIG. 10A; arrow B2). In other words, the paste pot 61 (emptypaste pot 61) having existed at the ejection position is positioned atthe standby position deviating from the ejection position, and the pastepot 61 (new paste pot 61) having existed at the standby position ispositioned at the ejection position. After the left paste pot 61 ispositioned at the ejection position, the controller 100 moves the pistonrod 55 a downward to protrude (FIG. 10B; arrow A1). Accordingly, theinner lid 72 is depressed with respect to the tubular container 71, andthe paste Pst is ejected downward from the left paste pot 61 (FIG. 10B).

When or after the pot holder 54 is switched from the second position tothe first position, the controller 100 actuates the notification device101 described above, and provides notification that the empty paste pot61 should be replaced with a new paste pot 61. Based on notificationoperation by the notification device 101, the operator OP watches for atiming when ejection operation of the paste Pst by the paste supplyapparatus 8 is not performed, and at the timing, the operator OP removesthe right empty paste pot 61 from the right pot insertion hole 54H (FIG.10C; arrow C1), and then inserts the new paste pot 61 into the right potinsertion hole 54H so as to hold the new paste pot 61 in the pot holder54. Accordingly, since the state changes (returns) to the state of FIG.7A described above, the paste supply operation can subsequently becontinued without running out of the paste Pst.

As described above, the paste supply apparatus 8 according to theembodiment includes the ejection completion detector 55 c which detectsthe completion of ejection of the paste Pst in the paste pot 61positioned at the ejection position, and if the ejection completiondetector detects the completion of ejection of the paste Pst in thepaste pot 61 positioned at the ejection position, the controller 100performs control such that the paste pot 61 (empty paste pot 61) havingexisted at the ejection position is moved to the standby positiondeviating from the ejection position and the paste pot 61 (new paste pot61) having existed at the standby position is moved to the ejectionposition.

Next, an execution procedure (screen printing method) of screen printingwork by the screen printing machine 1 will be described. In thisprocedure, at first, the operator OP operates an input unit 102 (FIG. 6)connected to the controller 100 for starting a predetermined screenprinting work. On receiving the input for starting the screen printingwork, the controller 100 receives and conveys the substrate 2 loadedfrom the outside of the screen printing machine 1 by the conveyors 16,and positions the substrate 2 at a work position of below a spacebetween the pair of clampers 18. After the second lifting table 14 ismoved upward with respect to the first lifting table 13 and a lowersurface of the substrate 2 is supported by the receiving member 17, thesecond lifting table 14 is moved further upward and the substrate 2 islifted from the conveyors 16, and both ends of the substrate 2 areclamped and held from the Y-axis direction by a pair of clampers 18.

After the substrate 2 is clamped, the controller 100 moves the cameraunit 7 to enter a space under the mask 5. The camera unit 7 images thesubstrate side marks 2 m provided on the substrate 2 from above thesubstrate 2 by the downward imaging camera 32, thereby obtaining imagedata of the substrate side marks 2 m. The camera unit 7 also images themask side marks 5 m provided on the mask 5 from below the mask 5 by theupward imaging camera 31, thereby obtaining image data of the mask sidemarks 5 m. Then, image recognition based on the obtained image data ofthe substrate side marks 2 m is performed to calculate a position of thesubstrate 2, and image recognition based on the image data of the maskside marks 5 m is performed to calculate a position of the mask 5.

After the position of the substrate 2 and the position of the mask 5 arecalculated, the controller 100 moves the camera unit 7 at a positiondeviating from the space under the mask 5. Then, actuation control ofthe XYθ movement mechanism 11 is performed to move the substrate 2 so asto position the substrate side marks 2 m under (e.g., just under) themask side marks 5 m. Accordingly, the positioning of the substrate 2 isperformed with respect to the mask 5.

After the substrate 2 is positioned with respect to the mask 5, thecontroller 100 moves the first lifting table 13 of the substrateholding/moving unit 4 upward with respect to the base table 12 (FIG. 11;arrow D). Accordingly, the electrodes 2 a of the substrate 2 match withthe pattern holes 5 h of the mask 5, and an upper surface of thesubstrate 2 and upper surfaces of the clampers 18 are positioned tocontact a lower surface of the mask 5 (a contact step).

After the substrate 2 is positioned to contact the mask 5, thecontroller 100 moves the squeegee base 21 in the Y-axis direction, andalso moves the paste supply apparatus 8 in a paste supply attitude at agiven or predetermined position (normally, at a position above a portionof the mask 5 which contacts the front clamper 18). Then, the pastesupply apparatus moving motor 44 is actuated so as to move the pastesupply apparatus 8 in the X-axis direction such that the pot holder 54is moved in a direction (X-axis direction) in which the two paste pots61 are arranged so as to selectively position one of the two paste pots61 at a given or predetermined ejection position (a pot holder movingstep). In this state, the inner lid 72 of the paste pot 61 positioned atthe ejection position is depressed with respect to the tubular container71, whereby the paste Pst is ejected from the through hole 61S of thepaste pot 61 (an ejecting step). Accordingly, the paste Pst is suppliedto the mask 5 (a paste supply step). In the paste supply step, if thenotification device 101 provides the notification that the empty pastepot 61 containing no paste Pst should be replaced with a new paste pot61, the operator OP performs replacement work of the paste pot 61according to this notification.

After the paste Pst is supplied to the mask 5, the controller 100 movesone squeegee 22 downward with respect to the squeegee base 21 so as toabut the lower end of the squeegee 22 on the mask 5, and moves thesqueegee base 21 in the Y-axis direction (FIG. 11; arrow E), whereby thesqueegee 22 is slid on the mask 5 (a squeegee sliding step).Accordingly, the paste Pst supplied to the mask 5 by the paste supplystep is scraped by the squeegee 22, and the paste Pst is transferred tothe electrodes 2 a of the substrate 2 through the pattern holes 5 h ofthe mask 5.

When the paste Pst is transferred, the controller 100 abuts the frontsqueegee 22 (left side of paper of FIG. 11) on the mask 5 when thesqueegee base 21 is moved from the front to the back of the screenprinting machine 1 (from the left to the right in FIG. 11), and abutsthe back squeegee 22 (right side of paper of FIG. 11) on the mask 5 whenthe squeegee base 21 is moved from the back to the front of the screenprinting machine 1 (from the right to the left in FIG. 11).

After the transfer work of the paste Pst is completed, the controller100 moves the first lifting table 13 downward so as to separate thesubstrate 2 from the mask 5. Further, holding (clamping) of thesubstrate 2 by a pair of clampers 18 is released, and thereafter, thesecond lifting table 14 is moved downward and the substrate 2 is loweredon the conveyors 16. Then, the conveyors 16 are actuated to carry thesubstrate 2 to the outside of the screen printing machine 1.Accordingly, the screen printing work per sheet of the substrate 2 iscompleted.

According to the screen printing machine 1 and the screen printingmethod by the screen printing machine 1 (the paste supply apparatus 8and the paste supply method by the paste supply apparatus 8) in theembodiment as described above, after ejection of the paste Pst in onepaste pot 61 (first paste pot) is completed, another paste pot 61(second paste pot) is positioned at the ejection position and also theempty (first) paste pot 61 is positioned at the position (standbyposition) deviating from the ejection position. Consequently, the pastePst can subsequently be ejected from the (second) paste pot 61. Further,during that period, the empty (first) paste pot 61 can be replaced witha new paste pot 61, whereby the paste pot 61 can be replaced withoutstopping operation of whole functions of the screen printing machine 1.Therefore, work efficiency can be improved.

As a modification of the above-described embodiment, the paste supplyapparatus 8 may be configured to open the through hole 61S of the pastepot 61 when the paste Pst is ejected from the paste pot 61, and closethe through hole 61S of the paste pot 61 when the paste Pst is notejected from the paste pot 61. For example, as shown in FIGS. 12A to12C, the paste supply apparatus 8 may include: a shutter member 111provided at a position capable of closing the through hole 61S of thepaste pot 61 positioned at the ejection position; and an operating rod112 joined to the shutter member 111; and an operating actuator 113provided on the lower end of the base plate 51 and configured to movethe operating rod 112 along the Y-axis direction. The controller 100operates the operating actuator 113 in conjunction with operation of thepressing cylinder 55. In this example, the controller 100 positions theshutter member 111 at an opened position of the through hole 61S whenthe pressing cylinder 55 is depressed (FIG. 12B), and positions theshutter member 111 at a closed position of the through hole 61S whendepression of the pressing cylinder 55 is stopped (FIG. 12C).Accordingly, in a state in which the paste Pst is left inside a tubularcontainer 71 in the paste pot 61, the paste Pst can be prevented fromleakage of the through hole 61S of the paste pot 61 which may soil asupply target of the paste Pst (for example, a substrate 2) with thepaste Pst.

In the embodiment described above, the pot holder 54 holds two pastepots 61 and the pot holder moving device (moving cylinder 52)selectively positions one of the two paste pots 61 at the ejectionposition. However, the number of paste pots 61 held by the pot holder 54is not limited to two, and may be arbitral as long as the number ofpaste pots 61 is multiple (i.e., two or more).

As described above, the embodiment of the invention provides a pastesupply apparatus, a screen printing machine, a paste supply method and ascreen printing method, which can replace a paste pot without stoppingoperation of whole functions of the screen printing machine.

Although the invention has been described in detail with reference tospecific embodiments, various changes or modifications may be madewithout departing from the spirit and scope of the invention.

This application is based on Japanese Patent Application No.2013-123505, filed Jun. 12, 2013, the entire contents of which areincorporated herein by reference.

What is claimed is:
 1. A paste supply apparatus comprising: a pluralityof paste pots, each of which comprises a tubular container which storespaste and which comprises a bottom portion provided with a through holeand a movable inner lid provided in the tubular container; a pot holderwhich holds the plurality of paste pots so as to be horizontallyarranged along an arrangement direction such that the through hole ofeach of the plurality of paste pots is directed downward and downwardmovement of the tubular container thereof is regulated; a pot holdermoving device which moves the pot holder along the arrangement directionand which selectively positions one of the plurality of paste pots at anejection position such that at least one of the plurality of paste potsis held on the pot holder at a position deviating from the ejectionposition; a pad member which depresses the inner lid of the paste potfrom above the ejection position; and a paste ejecting device whichpresses, by the pad member, the inner lid of the paste pot positioned atthe ejection position by the pot holder moving device with respect tothe tubular container and which ejects the paste stored in the tubularcontainer from the through hole, wherein each of the plurality of pastepots is movable together with the pot holder by the pot holder movingdevice along the arrangement direction from a position not under thepaste ejecting device to the ejecting position under the paste ejectingdevice.
 2. A screen printing machine comprising: a mask which ispositioned to contact a substrate; a paste supply apparatus according toclaim 1, which ejects and supplies the paste to the mask contacting thesubstrate; and a squeegee slid on the mask to which the paste issupplied by the paste supply apparatus.
 3. A screen printing methodcomprising: positioning a mask to contact a substrate; ejecting andsupplying the paste from the paste supply apparatus according to claim 1to the mask contacting the substrate; and sliding a squeegee on the maskto which the paste is supplied.
 4. A paste supply method comprising:holding a plurality of paste pots, each of which comprises a tubularcontainer which stores paste and which comprises a bottom portionprovided with a through hole and a movable inner lid provided in thetubular container, so as to be horizontally arranged along anarrangement direction in a pot holder such that the through hole of eachof the plurality of paste pots is directed downward and downwardmovement of the tubular container thereof is regulated; moving the potholder in the arrangement direction and selectively positioning one ofthe plurality of paste pots at an ejection position such that at leastone of the plurality of paste pots is held on the pot holder at aposition deviating from the ejection position; and pressing the innerlid of the paste pot positioned at the ejection position with respect tothe tubular container by a pad member from above the ejection positionand ejecting the paste stored in the tubular container from the throughhole, wherein each of the plurality of paste pots is movable togetherwith the pot holder by the pot holder moving device along thearrangement direction from a position not under the paste ejectingdevice to the ejecting position under the paste ejecting device.